Function Get-PendingReboot 
{ 
<# 
.SYNOPSIS 
    Gets the pending reboot status on a local or remote computer. 
 
.DESCRIPTION 
    This function will query the registry on a local or remote computer and determine if the 
    system is pending a reboot, from either Microsoft Patching or a Software Installation. 
    For Windows 2008+ the function will query the CBS registry key as another factor in determining 
    pending reboot state.  "PendingFileRenameOperations" and "Auto Update\RebootRequired" are observed 
    as being consistant across Windows Server 2003 & 2008. 
   
    CBServicing = Component Based Servicing (Windows 2008) 
    WindowsUpdate = Windows Update / Auto Update (Windows 2003 / 2008) 
    CCMClientSDK = SCCM 2012 Clients only (DetermineIfRebootPending method) otherwise $null value 
    PendFileRename = PendingFileRenameOperations (Windows 2003 / 2008) 
 
.PARAMETER ComputerName 
    A single Computer or an array of computer names.  The default is localhost ($env:COMPUTERNAME). 
 
.PARAMETER ErrorLog 
    A single path to send error data to a log file. 
 
.EXAMPLE 
    PS C:\> Get-PendingReboot -ComputerName (Get-Content C:\ServerList.txt) | Format-Table -AutoSize 
   
    Computer CBServicing WindowsUpdate CCMClientSDK PendFileRename PendFileRenVal RebootPending 
    -------- ----------- ------------- ------------ -------------- -------------- ------------- 
    DC01           False         False                       False                        False 
    DC02           False         False                       False                        False 
    FS01           False         False                       False                        False 
 
    This example will capture the contents of C:\ServerList.txt and query the pending reboot 
    information from the systems contained in the file and display the output in a table. The 
    null values are by design, since these systems do not have the SCCM 2012 client installed, 
    nor was the PendingFileRenameOperations value populated. 
 
.EXAMPLE 
    PS C:\> Get-PendingReboot 
   
    Computer       : WKS01 
    CBServicing    : False 
    WindowsUpdate  : True 
    CCMClient      : False 
    PendFileRename : False 
    PendFileRenVal :  
    RebootPending  : True 
   
    This example will query the local machine for pending reboot information. 
   
.EXAMPLE 
    PS C:\> $Servers = Get-Content C:\Servers.txt 
    PS C:\> Get-PendingReboot -Computer $Servers | Export-Csv C:\PendingRebootReport.csv -NoTypeInformation 
   
    This example will create a report that contains pending reboot information. 
 
.LINK 
    Component-Based Servicing: 
    http://technet.microsoft.com/en-us/library/cc756291(v=WS.10).aspx 
   
    PendingFileRename/Auto Update: 
    http://support.microsoft.com/kb/2723674 
    http://technet.microsoft.com/en-us/library/cc960241.aspx 
    http://blogs.msdn.com/b/hansr/archive/2006/02/17/patchreboot.aspx 
 
    SCCM 2012/CCM_ClientSDK: 
    http://msdn.microsoft.com/en-us/library/jj902723.aspx 
 
.NOTES 
    Author:  Brian Wilhite 
    Email:   bwilhite1@carolina.rr.com 
    Date:    08/29/2012 
    PSVer:   2.0/3.0 
    Updated: 05/30/2013 
    UpdNote: Added CCMClient property - Used with SCCM 2012 Clients only 
             Added ValueFromPipelineByPropertyName=$true to the ComputerName Parameter 
             Removed $Data variable from the PSObject - it is not needed 
             Bug with the way CCMClientSDK returned null value if it was false 
             Removed unneeded variables 
             Added PendFileRenVal - Contents of the PendingFileRenameOperations Reg Entry 
#> 
 
[CmdletBinding()] 
param( 
  [Parameter(Position=0,ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)] 
  [Alias("CN","Computer")] 
  [String[]]$ComputerName="$env:COMPUTERNAME", 
  [String]$ErrorLog 
  ) 
 
Begin 
  { 
    # Adjusting ErrorActionPreference to stop on all errors, since using [Microsoft.Win32.RegistryKey] 
        # does not have a native ErrorAction Parameter, this may need to be changed if used within another 
        # function. 
    $TempErrAct = $ErrorActionPreference 
    $ErrorActionPreference = "Stop" 
  }#End Begin Script Block 
Process 
  { 
    Foreach ($Computer in $ComputerName) 
      { 
        Try 
          { 
            # Setting pending values to false to cut down on the number of else statements 
            $PendFileRename,$Pending,$SCCM = $false,$false,$false 
                         
                        # Setting CBSRebootPend to null since not all versions of Windows has this value 
                        $CBSRebootPend = $null 
             
            # Querying WMI for build version 
            $WMI_OS = Get-WmiObject -Class Win32_OperatingSystem -Property BuildNumber, CSName -ComputerName $Computer 
 
            # Making registry connection to the local/remote computer 
            $RegCon = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey([Microsoft.Win32.RegistryHive]"LocalMachine",$Computer) 
             
            # If Vista/2008 & Above query the CBS Reg Key 
            If ($WMI_OS.BuildNumber -ge 6001) 
              { 
                $RegSubKeysCBS = $RegCon.OpenSubKey("SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\").GetSubKeyNames() 
                $CBSRebootPend = $RegSubKeysCBS -contains "RebootPending" 
                   
              }#End If ($WMI_OS.BuildNumber -ge 6001) 
               
            # Query WUAU from the registry 
            $RegWUAU = $RegCon.OpenSubKey("SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\") 
            $RegWUAURebootReq = $RegWUAU.GetSubKeyNames() 
            $WUAURebootReq = $RegWUAURebootReq -contains "RebootRequired" 
             
            # Query PendingFileRenameOperations from the registry 
            $RegSubKeySM = $RegCon.OpenSubKey("SYSTEM\CurrentControlSet\Control\Session Manager\") 
            $RegValuePFRO = $RegSubKeySM.GetValue("PendingFileRenameOperations",$null) 
             
            # Closing registry connection 
            $RegCon.Close() 
             
            # If PendingFileRenameOperations has a value set $RegValuePFRO variable to $true 
            If ($RegValuePFRO) 
              { 
                $PendFileRename = $true 
 
              }#End If ($RegValuePFRO) 
 
            # Determine SCCM 2012 Client Reboot Pending Status 
            # To avoid nested 'if' statements and unneeded WMI calls to determine if the CCM_ClientUtilities class exist, setting EA = 0 
            $CCMClientSDK = $null 
                        $CCMSplat = @{ 
                            NameSpace='ROOT\ccm\ClientSDK' 
                            Class='CCM_ClientUtilities' 
                            Name='DetermineIfRebootPending' 
                            ComputerName=$Computer 
                            ErrorAction='SilentlyContinue' 
                            } 
                        $CCMClientSDK = Invoke-WmiMethod @CCMSplat 
            If ($CCMClientSDK) 
                            { 
                                If ($CCMClientSDK.ReturnValue -ne 0) 
                      { 
                        Write-Warning "Error: DetermineIfRebootPending returned error code $($CCMClientSDK.ReturnValue)" 
                             
                      }#End If ($CCMClientSDK -and $CCMClientSDK.ReturnValue -ne 0) 
 
                    If ($CCMClientSDK.IsHardRebootPending -or $CCMClientSDK.RebootPending) 
                      { 
                        $SCCM = $true 
 
                      }#End If ($CCMClientSDK.IsHardRebootPending -or $CCMClientSDK.RebootPending) 
 
                            }#End If ($CCMClientSDK) 
                        Else 
                            { 
                                $SCCM = $null 
 
                            }                         
                         
                        # If any of the variables are true, set $Pending variable to $true 
            If ($CBSRebootPend -or $WUAURebootReq -or $SCCM -or $PendFileRename) 
              { 
                $Pending = $true 
 
              }#End If ($CBS -or $WUAU -or $PendFileRename) 
               
            # Creating Custom PSObject and Select-Object Splat 
                        $SelectSplat = @{ 
                            Property=('Computer','CBServicing','WindowsUpdate','CCMClientSDK','PendFileRename','PendFileRenVal','RebootPending') 
                            } 
            New-Object -TypeName PSObject -Property @{ 
                Computer=$WMI_OS.CSName 
                CBServicing=$CBSRebootPend 
                WindowsUpdate=$WUAURebootReq 
                CCMClientSDK=$SCCM 
                PendFileRename=$PendFileRename 
                                PendFileRenVal=$RegValuePFRO 
                RebootPending=$Pending 
                } | Select-Object @SelectSplat 
 
          }#End Try 
 
        Catch 
          { 
            Write-Warning "$Computer`: $_" 
             
            # If $ErrorLog, log the file to a user specified location/path 
            If ($ErrorLog) 
              { 
                Out-File -InputObject "$Computer`,$_" -FilePath $ErrorLog -Append 
 
              }#End If ($ErrorLog) 
               
          }#End Catch 
           
      }#End Foreach ($Computer in $ComputerName) 
       
  }#End Process 
   
End 
  { 
    # Resetting ErrorActionPref 
    $ErrorActionPreference = $TempErrAct 
  }#End End 
   
}#End Function